A Wake Forest Baptist Medical Center study, released Monday, has found that some people -- called "super emitters" by researchers -- may be better at transmitting influenza particles than others.
Dr. Werner Bischoff, an assistant professor of infectious diseases at Wake Forest Baptist and lead author of the study, said it is not clear whether these super emitters actually spread the flu to more people.
The study also determined that small flu particles can travel farther than the 6-foot reach that has been the common medical thought. "Smaller articles can float through the air for minutes, if not hours, so they can reach longer distances," he said.
The study, published on the website of the Journal of Infectious Disease, could lead to recommendations that health-care workers use a more elaborate and costlier mask -- known as a fitted respirator -- rather than just a non-fitted surgical facemask when treating patients with the flu.
The Centers for Disease Control and Prevention (CDC) currently recommends the use of a surgical mask for health-care providers. The CDC sponsored the Wake Forest Baptist study.
"Our study provides new evidence that infectiousness may vary between influenza patients and questions the current medical understanding of how influenza spreads," Bischoff said.
The study involved 94 patients who were screened for flu-like symptoms at Wake Forest Baptist's emergency department during the 2010-2011 flu season. Nasal swabs were collected from each patient, and air samples were obtained from within 1 foot, 3 feet and 6 feet of patients during routine care.
Of the 94 patients, 61 tested positive for the flu virus, with 26 having released influenza particles into the air through coughing and sneezing. Five people emitted up to 32 times more virus than the others, according to the study.
"One out of five influenza-emitting individuals released elevated amounts of virus into the environment, pointing to a highly infectious subgroup," Bischoff said. "Additionally, the patients who emitted more virus also reported greater severity of illness."
The study comes out as the 2012-13 flu season is expected to begin winding down after a surprisingly early and fatal start.
There have been 35 confirmed N.C. deaths -- all adults, and 27 of the victims were ages 65 or older -- related to influenza since the flu season began Oct. 1, according to N.C. Department of Health and Human Services data as of Jan. 26.
There have been 315 confirmed cases statewide, including 49 in the Triad and Northwest North Carolina. The last confirmed case in Forsyth County was found during the week that ended Dec. 8.
Bischoff said more research is being conducted to determine what characteristics make a person more likely to emit more influenza particles.
Bischoff said the study is likely to stir conversation about the use of fitted respirators since "health-care employees need to take precautions not just for their sake, but the sake of everybody around them."
"Of course, things like normal cough and sneeze etiquette can help reduce the spread of influenza, as well as getting the flu vaccine.
"We will continue to do research into the super emitters to determine if they can affect a lot of people within a short amount of time," Bischoff said.
Chad Campbell, a spokesman for Wake Forest Baptist, has said all employees, students, trainees and volunteers are required to get an annual immunization unless there is a medical or religious exemption.
"The medical center achieved 100 percent compliance with our 2012 influenza vaccination program, with a total of 13,034 immunized during our 2012 flu campaign," Campbell said. "No regularly scheduled employee has ever been terminated for not having a flu shot."
Jeanne Mayer, a spokeswoman for Novant Health Inc., said the system "encourages all staff, clinical and non-clinical, to get vaccinated," but it is not mandatory. "Any employee not vaccinated who works within 6 feet of patients must wear a surgical mask during flu season," Mayer said.
The flu is a contagious respiratory illness caused by viruses that infect the nose, throat and lungs. It usually spreads when people who have the flu virus cough, sneeze or talk. Most people who get the flu will be sick only two to seven days.
Health officials say anyone who develops more severe symptoms -- difficulty breathing, severe nausea, vomiting, diarrhea, abdominal pain or chest pain -- should get medical attention.
A flu vaccine is recommended for anyone older than 6 months, particularly for people at high risk of complications, such as pregnant women, people with chronic diseases, very young children and the elderly. Government health experts recommend people get vaccinated as soon as possible since it takes two weeks after getting vaccinated for the immunity to kick in.
The vaccine is available for free at the Forsyth County Department of Public Health at 799 N. Highland Ave. in downtown Winston-Salem. For more information, call (336) 793-3100. Local hospitals, many pharmacies and individual physician practices also have the vaccines, usually for a fee.
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